Fix build against xorg-server >= 1.20.

Patch taken from upstream:
https://cgit.freedesktop.org/xorg/driver/xf86-video-savage/commit/?id=0ece556daa8a88771b669d8104396abd9166d2d0

diff --git a/src/savage_driver.c b/src/savage_driver.c
index 58a294d..3cda923 100644
--- a/src/savage_driver.c
+++ b/src/savage_driver.c
@@ -2034,8 +2034,6 @@ static Bool SavagePreInit(ScrnInfoPtr pScrn, int flags)
     xf86DrvMsg(pScrn->scrnIndex, X_PROBED, "Detected current MCLK value of %1.3f MHz\n",
 	       mclk / 1000.0);
 
-    pScrn->maxHValue = 2048 << 3;	/* 11 bits of h_total 8-pixel units */
-    pScrn->maxVValue = 2048;		/* 11 bits of v_total */
     pScrn->virtualX = pScrn->display->virtualX;
     pScrn->virtualY = pScrn->display->virtualY;
 
@@ -3637,6 +3635,14 @@ static ModeStatus SavageValidMode(SCRN_ARG_TYPE arg, DisplayModePtr pMode,
        (pMode->VDisplay > psav->PanelY)))
 	    return MODE_PANEL;
 
+    /* 11 bits of h_total 8-pixel units */
+    if (pMode->HTotal > (2048 << 3))
+	return MODE_BAD_HVALUE;
+
+    /* 11 bits of v_total */
+    if (pMode->VTotal > 2048)
+	return MODE_BAD_VVALUE;
+
     if (psav->UseBIOS) {
 	refresh = SavageGetRefresh(pMode);
         return (SavageMatchBiosMode(pScrn,pMode->HDisplay,
ix/tree/tests/gnu-maintenance.scm?id=752a5b8fe5c949627b7f68a2780549ba13276403'>tree</a><a href='/guix/commit/tests/gnu-maintenance.scm?id=752a5b8fe5c949627b7f68a2780549ba13276403'>commit</a><a href='/guix/diff/tests/gnu-maintenance.scm?id=752a5b8fe5c949627b7f68a2780549ba13276403'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/tests/gnu-maintenance.scm'>
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<tr><td><span title='2021-05-28 23:04:44 +0200'>2021-05-28</span></td><td><a href='/guix/commit/tests/gnu-maintenance.scm?id=d7c356edb9719f1e236ee926c0288f914076481a'>gnu-maintenance: 'release-file?' accepts 'v' prefix as in "PKG-v1.2.tgz".</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/gnu-maintenance.scm (%tarball-rx, %package-name-rx): Accept 'v'
and 'V' prefixes.  Accept ".tgz" extension.
* tests/gnu-maintenance.scm ("release-file?"): Add test.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-04-05 12:03:09 +0200'>2021-04-05</span></td><td><a href='/guix/commit/tests/gnu-maintenance.scm?id=ceeea60bbc1e2be6a86cef208fcd80eb61c92934'>gnu-maintenance: Recognize more source tarball naming schemes.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/gnu-maintenance.scm (%package-name-rx): Add ".src" and ".orig"
suffixes.
* tests/gnu-maintenance.scm ("release-file?"): Add mpg321 and bvi
examples.
("tarball-&gt;version"): New test.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-03-29 23:33:40 +0200'>2021-03-29</span></td><td><a href='/guix/commit/tests/gnu-maintenance.scm?id=1575da60628cf2594cd7b1ab0812ec4c50ac5092'>gnu-maintenance: Recognize "-source" tarball suffix.</a><span class='msg-avail'>...<span class='msg-tooltip'>Fixes &lt;https://bugs.gnu.org/47398&gt;.
Reported by Léo Le Bouter &lt;lle-bout@zaclys.net&gt;.

* guix/gnu-maintenance.scm (%tarball-rx): Add "-[Ss]ource" suffix.
* tests/gnu-maintenance.scm ("release-file?"): Add exiv2 example.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-03-20 22:29:14 +0100'>2021-03-20</span></td><td><a href='/guix/commit/tests/gnu-maintenance.scm?id=1710e8cb59e2ef6f1e0eb19235b6a4f1b8158bc4'>gnu-maintenance: Accept underscores as package/version separators.</a><span class='msg-avail'>...<span class='msg-tooltip'>Fixes &lt;https://bugs.gnu.org/47256&gt;.
Reported by Léo Le Bouter &lt;lle-bout@zaclys.net&gt;.

* guix/gnu-maintenance.scm (%tarball-rx, %package-name-rx): Accept
underscore as the package/version separator in tarball names.
* tests/gnu-maintenance.scm ("release-file?"): Add "mediainfo" test.
</span></span></td><td>Ludovic Courtès</td></tr>